Various implants have been proposed for repairing abdominal wall defects such as direct and indirect inguinal hernias. Inguinal hernias occur when the peritoneum (lining of the abdominal cavity) and bowel pass into the inguinal canal through a hole in the innermost muscle layer called the transversalis fascia. An indirect hernia forms when a portion of the intestine passes through the internal ring and courses obliquely down the inguinal canal. A direct hernia involves the rupture of the inguinal canal floor adjacent the internal ring. An indirect hernia is marked by a long tubeshaped defect while a direct hernia is identified by a shallow hole.
Classical repair of inguinal hernias (reparative herniorrhaphy) requires a two inch or longer incision through the abdominal wall. The many layers of healthy tissue are then retracted by the physician to expose the void. The healthy muscle and tissue which have been incised to reach the rupture site require a long period of recovery (six days or longer) and result in substantial postoperative pain.
A laparoscopic hernia repair technique recently proposed uses an illuminating optical instrument (laparoscope) which is inserted through a thin tube (trocar cannula) in the abdominal wall to visualize the interior of the abdominal cavity. The entire surgical procedure takes place using special surgical tools manipulated through additional cannulae extending through the abdominal wall. Laparoscopic surgery minimizes patient discomfort and recovery time, allows diagnosis without invasive surgery and lessens the risk of traumatic injury to the abdominal tissues.
Various mesh prostheses have been proposed for use in laparoscopic hernia repair. Representative are the mesh fabric logs or plugs 5 illustrated in FIG. 1 which are formed by rolling sheets of mesh into cylinders and then suturing the ends. The logs are inserted into the defect 6 until the void is filled. A larger flat piece of mesh 7, commonly referred to as an onlay patch, is placed over the herniated opening, holding the logs in place. The mesh materials become bound in place as tissue grows through the fabric.
The use of mesh logs or plugs may suffer from certain deficiencies. Overstuffing of the void may lead to occlusion of a testicular vessel and, potentially, testicular swelling or atrophy. Further, the mesh logs may cause a bulky protrusion which the patient can feel, although the sensation should decrease over time. Lastly, the use of customized plugs and logs does not lend itself to a standardized surgical procedure.
A composite mesh prosthesis suitable for use in classical and laparoscopic surgery is disclosed in commonly assigned U.S. Pat. No. 5,593,441 issued to Lichtenstein et al., entitled "Method For Limiting The Incidence Of Postoperative Adhesions", the disclosure of which is specifically incorporated herein by reference. The composite implant includes a tissue infiltratable fabric and an adhesion barrier which isolates the inflammatory mesh from sensitive tissue such as the abdominal viscera.
Various tools have been proposed in the art for loading and delivering the mesh implants through the trocar cannula and into the abdominal cavity. In the case of the mesh logs, typically one end of the log is held by a grasper which is then retracted into the lumen of an introducer tube. The rear-end loaded introducer and grasper are inserted into and through the trocar cannula. That technique may have certain disadvantages including the need to coordinate a separate introducer and grasper instrument to collapse the implant and then deliver the implant to the hernia site.
Accordingly, the prior art lacks a mesh implant suitable for laparoscopic repair which effectively occludes the hernia defect without stuffing the void. The prior art also lacks a single and efficient tool for collapsing and delivering an implant through a trocar cannula to a defect site.